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Contract No. DE-AC36-08GO28308

Renewable Hydrogen Potential 

from Biogas in the United States

G. Saur and A. Milbrandt

National Renewable Energy Laboratory

Technical Report

NREL/TP-5400-60283

July 2014
NREL is a national laboratory of the U.S. Department of Energy

Office of Energy Efficiency & Renewable Energy

Operated by the Alliance for Sustainable Energy, LLC

This report is available at no cost from the National Renewable Energy

Laboratory (NREL) at www.nrel.gov/publications.

Contract No. DE-AC36-08GO28308

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15013 Denver West Parkway

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Renewable Hydrogen Potential 

from Biogas in the United States 

G. Saur and A. Milbrandt

National Renewable Energy Laboratory

Prepared under Task No. HT12.2010

Technical Report

NREL/TP-5400-60283

July 2014
NOTICE

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iii

Acknowledgments

Funding for this report came from the U.S. Department of Energy’s Fuel Cell Technologies 

Office. The authors would like to specifically thank Fred Joseck, U.S. Department of Energy, for 

his guidance and support. We would also like to thank those involved with data gathering at the 

U.S. Environmental Protection Agency, U.S. Department of Agriculture, and U.S. Census 

Bureau, without which this analysis could not have been completed. This report was peer 

reviewed by Marc Melaina from the National Renewable Energy Laboratory (NREL), Dr. 

Michael Schuppenhauer from Farmatic, Inc., Christopher Yang from University of California, 

Davis, and Yongling Sun from NREL. 

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iv

Nomenclature

Btu British thermal unit

CH4 methane 

CHP combined heat and power 

EPA U.S. Environmental Protection Agency 

FCEV fuel cell electric vehicle

gge gasoline gallon equivalent 

H2 hydrogen 

HSIP U.S. Homeland Security Infrastructure Program

IIC industrial, institutional, and commercial

kg kilogram 

lb pound 

LFG landfill gas

LMOP Landfill Methane Outreach Program 

scf standard cubic feet

SMR steam methane reforming

tonne metric ton

VS volatile solids

WIP waste in place

WWTP wastewater treatment plant

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v 

Executive Summary

Biogas resources present an opportunity to address several key energy and environmental issues. 

Biogas contains significant amounts of methane, which can be used as a fuel for a variety of 

electricity and transportation applications [1]. It can help decrease greenhouse gas emissions and 

other environmental pollution to the air and water. Biogas is produced by anaerobic digestion, a 

process in which organic matter is broken down in an oxygen-free environment. The organic 

matter for anaerobic digestion can originate from a wide range of waste streams, such as 

municipal solid waste, discards from food processing, animal manure, sewage, stillage and 

glycerin from biofuels production, as well as energy crops and agricultural residues. The use of 

these waste streams for methane production by anaerobic digestion helps to reduce the amount of 

waste that must be disposed of using other methods that generally do not have environmental 

benefits. Anaerobic digestion can also produce other useful by-products in addition to the biogas, 

such as fertilizer, and can be a precursor for industrial chemicals and polymers.

This analysis updates and expands upon previous biogas studies to include total potential and net 

availability of methane in raw biogas with respect to competing demands and includes a resource 

assessment of four sources of biogas: (1) wastewater treatment plants (WWTPs), including 

domestic and a new assessment of industrial sources; (2) landfills; (3) animal manure; and (4) a 

new assessment of industrial, institutional, and commercial (IIC) sources [2, 3]. The net 

availability is calculated differently for each resource as follows: WWTPs are cross-referenced 

with a database of existing combined heat and power plants utilizing biogas captured from the 

WWTP [12], landfill net availability is calculated using the candidate sites that the U.S. 

Environmental Protection Agency (EPA) has identified for their strong energy project potential 

[18], and animal manure net availability is a reduction of the total from an estimate of existing 

digesters [24]. 

The results of the biogas resource assessment are used to estimate the potential production of 

renewable hydrogen from biogas as well as the fuel cell electric vehicles (FCEVs) that the 

produced hydrogen might support. The U.S. total methane potential in raw biogas from the 

sources examined here is estimated at about 16 million tonnes, but the net availability calculated 

is about 6.2 million tonnes (Table ES-1). For comparison, the U.S. natural gas consumption in 

2013 was about 573 million tonnes [35]. The geographic distribution is also provided to help 

inform regional policies that might support increased utilization of biogas resources. The 

estimates do not include electricity, water, or other materials that may also be required in the 

biogas, biomethane, and hydrogen production processes. The geographic distribution of the 

analyzed biogas sources is shown in Figure ES-1. 

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vi 

Table ES-1. U.S. Methane and Hydrogen Potentials by Source

Source Methane Potential

(thousand tonnes/yr)

Hydrogen Potential

(thousand tonnes/yr)

Total Available Total Available

WWTPs

a 2,339 1,927 618 509

Landfillsb 10,586 2,455 2,795 648

Animal manurec 1,905 1,842 503 486

IIC organic waste 1,158 N/A 306 N/A

Total 15,988 6,224 4,221 1,643 a Total potential for WWTPs is higher, given that the analysis was done for only half of the WWTPs in the country 

(water flow data for the rest is missing). 

b Total potential for landfills could be higher given that the estimate accounts for only the WIP recorded for a given 

year and does not take into account additional waste that may have come in since the record was taken (as it was 

done for the “available potential” estimate). It is an approximate value. Available potential for landfills is estimated 

using candidate landfills only. Available potential could be higher if we include "other" and "potential" landfills.

c Existing digesters (dairy, poultry, and swine) capture about 62,942 tonnes/yr [24].

Figure ES-1. Methane and hydrogen potential from combined biogas sources in the United States

by county

Landfills, in this study, represent the largest potential source of methane and hydrogen from both 

a total perspective as well as the current net availability. The total potential of methane in raw 

biogas is approximately 10.6 million tonnes of methane, or, if converted to hydrogen, about 2.8 

million tonnes of hydrogen per year.1

 This total potential could be higher due to data recording 

gaps in landfill waste in place reporting (i.e., the quantity of waste at the site). The net potential 

 

1 The conversion to hydrogen assumes 87% of the methane content in the biogas can be purified to biomethane and 

a conversion factor of 3.3 kg CH4/kg hydrogen for hydrogen production from biomethane.

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vii 

of landfills is estimated at 2.5 million tonnes of methane or 648,000 tonnes of hydrogen1

annually [18]. This net availability could be a conservative estimate because it does not include 

sites listed by the EPA as “potential” or “other,” some of which might make feasible projects 

along with “candidate” sites. The top 20 counties in the United States for producing biogas from 

landfills account for more than 30% of the net availability but less than 10% of the number of 

landfill sites.

WWTPs can be a significant source of methane for hydrogen production. The total U.S. potential 

of methane in raw biogas for sites analyzed2 is 2.3 million tonnes, which is approximately 

618,000 tonnes of hydrogen per year.1 Some sites have existing combined heat and power 

projects, which decrease the total amount of methane that might be available for hydrogen. We 

calculated the net availability of methane at WWTPs to be about 1.9 million tonnes of methane 

or, if converted to hydrogen, about 509,000 tonnes of hydrogen1 [12]. The net availability is 

about 17% less than the total potential. Of the WWTPs analyzed, more than 90% have 

production capacities of less than 80 tonnes of hydrogen. 

Animal manure is a more dispersed resource found in rural areas tending toward more, smaller 

sites than WWTPs and landfills. However, it can be a significant source of biogas if some of the 

economic issues of collection and aggregation can be overcome. The total methane potential in 

raw biogas from the three animal types studied (dairy cows, hogs, and broiler chickens) is 

estimated at about 1.9 million tonnes annually, which, if converted to hydrogen, would result in 

about 503,000 tonnes of hydrogen.1

 Existing digesters capture about 63,000 tonnes of methane, 

reducing the net availability to about 1.8 million tonnes of methane or 486,000 tonnes of 

hydrogen [24]. The top 20 counties in the United States for producing biogas from animal 

manure represent almost 32% of the U.S. total potential and could be a source of hydrogen for 

bridging transportation corridors between major metropolitan areas and bringing economic 

opportunities for rural areas. 

The total potential from IIC sources is slightly less than from the other biogas sources examined, 

yet it still represents a significant source of methane and hydrogen. Only total potential is 

calculated in this new analysis. The total methane potential in raw biogas from IIC sources is 

estimated to be 1.2 million tonnes annually, or 306,000 tonnes of hydrogen.1

 The top 20 counties 

in the United States for producing biogas from IIC sources represent almost 20% of the total 

potential of IIC sources. 

The number of FCEVs potentially supported by renewable hydrogen from biogas is estimated by 

assuming an average FCEV fuel economy of 56.5 miles per gasoline gallon equivalent and 

average annual miles traveled per vehicle of 10,000 miles per year. The total number of vehicles 

supported from all biogas sources—using net availability where available—if the methane is 

converted to hydrogen is about 11 million FCEVs annually, with landfills accounting for more 

than a third of that at 3.7 million FCEVs annually. The breakdown by biogas source is shown in 

Figure ES-2. 

 

2 The actual total potential and net availability could be higher, as only about half the sites analyzed included 

wastewater flow data needed to make the calculations.

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viii

* IIC is total potential.

Figure ES-2. The number of FCEVs supported by biogas source, utilizing the net availability of the 

biogas source (with the exception of IIC)

This study also presents results from two regional analyses performed on the Sacramento, 

California, and Boston, Massachusetts, areas using net availability of the biogas resources where 

available. The potential from all sources for the Sacramento region is about 93,300 tonnes of 

hydrogen annually, which could support almost 527,300 FCEVs. The Boston region has about 

33,000 tonnes of hydrogen potential annually, which could support approximately 186,700 

FCEVs.

Renewable hydrogen from biogas has the potential to aid early FCEV rollout. It is a local, 

sustainable resource, and based on this study, it can supply about 5% of the current U.S. lightduty vehicle fleet3

 if that portion were replaced by FCEVs. The biogas resources available 

locally to any given area will vary by region. The introduction of increased amounts of FCEVs 

into the vehicle fleet could have environmental benefits. The transportation sector is second only 

to the electric sector in greenhouse gas emissions, and renewable hydrogen used in FCEVs can 

offer environmental benefits.

Relying upon a renewable source of hydrogen would help highlight the clean car profile of 

FCEVs during early market introduction, and the state of California already has requirements for 

renewable hydrogen production. However, development of these biogas resources has challenges 

that may be unique for any given region, state, or urban area. State and local policies, rapport 

with local utilities, and the favor of local sources and stakeholders will all factor into successful 

project investment and resource development. 

 

3 The vehicle registrations in 2010 for cars and light-duty trucks (two axles, four tires) were approximated at 131 

million and 99.5 million respectively [31].

This report is available at no cost from the National Renewable Energy Laboratory (NREL) at www.nrel.gov/publications.
ix

Table of Contents

List of Figures ............................................................................................................................................. x

List of Tables ............................................................................................................................................... x

List of Equations ......................................................................................................................................... x

1 Introduction........................................................................................................................................... 1

2 Overview of Biogas Conversion to Hydrogen................................................................................... 2

3 Resource Assessments....................................................................................................................... 3

3.1 Wastewater Treatment Plants .......................................................................................................... 3

3.1.1 Methodology ..................................................................................................................... 3

3.1.2 Potential ............................................................................................................................ 4

3.2 Landfills........................................................................................................................................... 6

3.2.1 Methodology ..................................................................................................................... 6

3.2.2 Potential ............................................................................................................................ 7

3.3 Animal Manure .............................................................................................................................. 10

3.3.1 Methodology ................................................................................................................... 10

3.3.2 Potential .......................................................................................................................... 11

3.4 Industrial, Institutional, and Commercial ...................................................................................... 13

3.4.1 Methodology ................................................................................................................... 13

3.4.2 Potential .......................................................................................................................... 14

4 Vehicles Supported by Renewable Hydrogen................................................................................. 16

5 Discussion........................................................................................................................................... 17

5.1 Resource Sensitivities.................................................................................................................... 17

5.2 U.S. National Methane and Hydrogen Potential............................................................................ 18

5.3 Comparison to Previous Study....................................................................................................... 20

5.4 Select U.S. Local Regions ............................................................................................................. 21

5.4.1 Northern California ......................................................................................................... 21

5.4.2 Boston, Massachusetts.................................................................................................... 23

6 Biogas Purification Challenges......................................................................................................... 25

7 Conclusions ........................................................................................................................................ 28

8 Future Work......................................................................................................................................... 29

References................................................................................................................................................. 30

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x 

List of Figures

Figure ES-1. Methane and hydrogen potential from combined biogas sources in the United States 

by county.............................................................................................................................................. vi

Figure ES-2. The number of FCEVs supported by biogas source, utilizing the net availability of the 

biogas source (with the exception of IIC) ....................................................................................... viii

Figure 1. Distribution of WWTPs by hydrogen potential ........................................................................ 5

Figure 2. Methane and hydrogen potential from WWTPs by point source location ............................ 6

Figure 3. Distribution of landfill sites by hydrogen potential................................................................. 9

Figure 4. Available methane and hydrogen potential from landfills by point source location........... 9

Figure 5. Total methane and hydrogen potential from animal manure in the United States by 

county.................................................................................................................................................. 13

Figure 6. Methane and hydrogen potential from IIC sources in the United States by county .......... 15

Figure 7. The number of FCEVs supported by biogas source, utilizing the net availability of the 

biogas source (with the exception of IIC) ........................................................................................ 16

Figure 8. Relative intensity and range of hydrogen potential from biogas sources.......................... 18

Figure 9. Methane and hydrogen potential from combined biogas sources in the United States by 

county.................................................................................................................................................. 20

Figure 10. Net (as available) hydrogen potential from biogas in Northern California ....................... 22

Figure 11. Net (as available) hydrogen potential from biogas in Boston, Massachusetts................ 24

List of Tables

Table ES-1. U.S. Methane and Hydrogen Potentials by Source............................................................ vi

Table 1. Hydrogen Potential from WWTPs for the United States and the Top 20 Counties................ 5

Table 2. Hydrogen Potential from Landfills in Top 20 U.S. Counties .................................................... 8

Table 3. Hydrogen Potential from Animal Manure for the United States and in the Top 20 U.S. 

Counties .............................................................................................................................................. 12

Table 4. Methodology for Estimating Organic Waste from IIC Sources [29] ...................................... 14

Table 5. Hydrogen Potential from IIC Sources in the Top 20 U.S. Counties....................................... 15

Table 6. FCEVs Supported and Percentage of U.S. Fleet by Biogas Source, Utilizing the Net 

Availability of the Biogas Source (with the Exception of IIC)........................................................ 17

Table 7. Range of Methane Content in Biogas....................................................................................... 18

Table 8. U.S. Methane and Hydrogen Potentials by Source................................................................. 19

Table 9. Review of Previous Study.......................................................................................................... 21

Table 10. Net (As Available) Hydrogen Potential By Biogas Source in Northern California............. 23

Table 11. Net (As Available) Hydrogen Potential of Top 20 Counties in Northern California ........... 23

Table 12. Net (As Available) Hydrogen Potential By Biogas Source in the Boston Region ............. 25

Table 13. Net (As Available) Hydrogen Potential of Top 20 Counties in the Boston Region............ 25

Table 14. Biomethane Quality Requirements for Injection into Natural Gas Pipelines ..................... 26

Table 15. Biogas and Biomethane Constituents of Concern Developed for California AB 1900 ..... 27

List of Equations

Equation 1. Biogas to biomethane purification factor ............................................................................ 3

Equation 2. Biomethane to hydrogen conversion................................................................................... 3

Equation 3. Annual methane potential equation for WWTPs [10].......................................................... 4

Equation 4. Annual methane potential for landfills ................................................................................. 7

Equation 5. Volatile solids produced by animal type............................................................................ 10

Equation 6. Methane emissions for each animal type and manure management system ................ 10

Equation 7. Summation of methane across animal types and manure management systems........ 11

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1 

1 Introduction

Biogas is produced by anaerobic digestion, a process in which organic matter is broken down in 

an oxygen-free environment producing significant amounts of methane. The organic matter for 

anaerobic digestion can originate from a wide range of waste streams, such as municipal solid 

waste, discards from food processing, animal manure, sewage, stillage and glycerin from 

biofuels production, as well as energy crops and agricultural residues. The use of these waste 

streams for methane production by anaerobic digestion helps to reduce the amount of waste that 

must be disposed of using other methods that generally do not have environmental benefits. 

Biogas is made up primarily of 50%–70% methane and the rest carbon dioxide with trace 

amounts of other particulates and contaminants. Anaerobic digestion can also produce other 

useful by-products in addition to the biogas, such as fertilizer, and can be a precursor for 

industrial chemicals and polymers. Biogas resources present an opportunity to address several 

key energy and environmental issues because it can be used as a fuel for a variety of electricity 

and transportation applications [1]. Reducing waste through the use of anaerobic digestion can 

help decrease greenhouse gas emissions and other environmental pollution to the air and water.

The methane content of biogas is a renewable fuel that can support energy independence from 

imported petroleum when used in the transportation sector. One area of interest is as a source for 

renewable hydrogen, which can be used in stationary fuel cells and support the early market 

introduction of fuel cell electric vehicles (FCEVs). Hydrogen-powered FCEVs emit no tailpipe 

emissions other than water and are a clean transportation alternative to gasoline vehicles. In the 

United States, most hydrogen is produced by steam methane reforming (SMR) of natural gas. 

The same SMR technology can also use purified biogas, or biomethane, as a natural gas 

substitute to provide a lower carbon and renewable source of hydrogen. Producing hydrogen 

from biomethane provides a hedge against demand for fossil fuels and aids compliance with state 

policies on renewable fuels.

This analysis updates and expands upon previous biogas studies to include total potential and net 

availability of methane in raw biogas and includes a resource assessment of four sources of 

biogas: (1) wastewater treatment plants (WWTPs), including domestic and a new assessment of 

industrial sources; (2) landfills; (3) animal manure; and (4) a new assessment of industrial, 

institutional, and commercial (IIC) sources [2, 3]. The analysis addresses both the total resource 

available as well as a net availability with respect to currently competing demands for biogas. 

This resource assessment estimates the potential production of renewable hydrogen from biogas, 

as well as the FCEVs that it might support. The geographic distribution is also provided to help 

inform regional policies that might support increased utilization of biogas resources. The 

estimates do not include electricity, water, or other materials that may also be required in the 

biogas, biomethane, and hydrogen production processes.

Biogas production and subsequent purification to more readily useful products, such as 

biomethane, can incur significant costs, which is often due to the dispersed nature of biogas 

sources and economies of scale. This analysis begins to identify potential production system 

sizes and the geographic element of aggregating dispersed sources into larger, economically 

viable systems.

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2 

Biogas and renewable hydrogen from biogas will not meet all U.S. energy demands, but there is 

a growing interest and market for biogas and its use in fuel cells. However, it does have the 

potential of being a significant resource that can offset the growing dependence of the United 

States on fossil fuel use. These renewable energies can help foster energy independence, reduce 

air and water pollution, and decrease greenhouse gas emissions in the future. 

2 Overview of Biogas Conversion to Hydrogen

There are three main calculations necessary for estimating the potential hydrogen from select 

biogas resources: (1) the resource assessment of the methane content in biogas, (2) biogas 

purification for natural-gas-quality biomethane, and (3) biomethane conversion to hydrogen. The 

methodology for estimating the resource potential is addressed in Section 3 for each biogas 

source. These calculations are specific to each resource category. All references to the methane 

potential show the methane content of biogas before any cleanup of carbon dioxide and other 

contaminants. The biogas purification and conversion to hydrogen are addressed in common for 

all resource categories.

The resource assessment in Section 3 provides the methane potential of raw biogas for each 

source by either assessing the methane content directly or by calculating the biogas potential and 

estimating the percent methane contained in it. The hydrogen potentials assume a conversion of 

the methane in biogas to biomethane, which is natural gas quality, and subsequent conversion by 

SMR to hydrogen. Potential pathways for biomethane include injection into natural gas 

pipelines, use as a feedstock in an SMR process for conversion to hydrogen, and other natural 

gas end uses such as stationary heat and power. Sections 4 and 5 address the FCEVs that could 

be supported, along with additional national and regional analyses and resource sensitivities, by 

the conversion of biogas into hydrogen. Some end-use applications may not require the same 

level of biogas purification as used in this report. These considerations are discussed in Section 

6. 

To calculate the biomethane potential, the process of purifying the methane content in biogas 

must be characterized. Various chemical and biological purification processes are available on 

the biogas market. Membrane purification, a purely physical process, has been gaining interest in 

recent years [4]. In this process, a thin membrane is used to separate the methane from the input 

biogas stream, which is composed mainly of methane, carbon dioxide, and saturated water. The 

methane stream is then approximately natural gas quality although some other processing may be 

required to remove specific contaminants. The other output stream, the tail gas, is mainly carbon 

dioxide with a small amount of methane. This tail gas is combusted in a thermal oxidizer to 

minimize the methane emissions. The process uses both electricity for compression to aid

passing through the membrane and biogas as fuel for the thermal oxidizer. The efficiency of 

separating biomethane from biogas has been estimated to be 87%, which includes a membrane 

efficiency of 90% and a small share of input biogas being combusted in the thermal oxidizer to 

reduce emissions [4-6]. Therefore, the biomethane potential is 87% of the total methane 

available in the original biogas, as shown in Equation 1. This reduction factor is due to losses in 

upgrading and purifying the biogas to biomethane. The electricity usage is not considered in this 

report, but it would be included in total system life-cycle analyses.

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3 

Equation 1. Biogas to biomethane purification factor 

biomethane potential = 87% ∗ methane content of biogas

Once the biogas has been upgraded to natural-gas-quality biomethane, it can be used as a 

substitute for natural gas in an SMR process to produce hydrogen. The conversion factor for 

converting biomethane to hydrogen is taken from the U.S. Department of Energy’s H2A 

Production model case study for central production of hydrogen from natural gas [7]. The natural 

gas feedstock usage for the case study is 0.15625 million British thermal units (Btu) per kilogram 

(kg) hydrogen (H2). The energy content in natural gas is mainly methane (CH4), and this 

feedstock usage is converted to a conversion factor of 3.295 kg CH4/kg hydrogen using the 

factors shown in Equation 2. The process electricity is not considered for the SMR in this 

analysis, but it would be included in total system life-cycle analyses.

Equation 2. Biomethane to hydrogen conversion

0.15625 mmBtu

kg H2

∗

1055056 kJ

mmBtu ∗

mol CH4

802.5 kJ ∗ 16.04gmol CH4

∗ 1 kg

1000 g

= 3.295 kg CH4

kg H2

3 Resource Assessments

Resource assessments give an estimate of the quantity of resources available. They are useful in 

understanding the resource’s potential and how it may compare to other resources of similar 

resulting by-products. 

3.1 Wastewater Treatment Plants

WWTPs are facilities designed to remove biological, physical, and chemical contaminants from 

wastewater, therefore permitting the treated water to be used for other purposes. WWTPs can 

include domestic, agricultural, and industrial sources of wastewater.

3.1.1 Methodology

The data for WWTPs were obtained from the U.S. Environmental Protection Agency’s (EPA’s) 

2008 Clean Watersheds Needs Survey [8]. The data are collected every four years by the EPA 

and states to comprehensively assess the water quality goals set in the Clean Water Act. The 

database includes information from four main categories of WWTPs: 

• Publicly owned wastewater collection and treatment facilities

• Stormwater and combined sewer overflows control facilities

• Nonpoint-source pollution control projects 

• Decentralized wastewater management.

The database includes approximately 35,000 records with location point sources, of which only 

about 18,000 included the wastewater flow in million gallons per day. This analysis only uses 

these 18,000 records.

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4 

The biogas potential from the wastewater is estimated to be about 1 cubic foot (ft3) per 100 

gallons of wastewater [9-11]. The biogas is assumed to be 65% methane by volume, and the 

methane content of the biogas was estimated using methodology from the “Inventory of U.S. 

Greenhouse Gas Emissions and Sinks: 1990-2011” [10]. The annual methane potential is 

calculated as shown in Equation 3. In the results, the hydrogen potentials include a reduction of 

the methane from purification of the biogas and conversion by SMR as discussed in Section 2. 

Equation 3. Annual methane potential equation for WWTPs [10] 

annual methane potential

= q ∗

1 ft3 biogas

100 gal wastewater ∗

0.0283 m3 biogas

ft3 biogas ∗

65% m3 CH4

m3 biogas ∗

0.662 kg CH4

m3 CH4

where q is the wastewater flow in gallons per year.

The net availability was calculated by cross-referencing the identified sites with a database of 

existing combined heat and power (CHP) plants utilizing biogas captured from a WWTP [12]. In 

other words, WWTPs with existing CHP projects were not considered in the net availability 

potential. 

3.1.2 Potential

WWTPs can be a significant source of methane for hydrogen production. The total U.S. potential 

of methane in raw biogas from the sites analyzed is 2.3 million tonnes annually, which, 

converted to hydrogen, is approximately 618,000 tonnes of hydrogen. Some sites have an 

existing CHP project, which decreases the total amount of methane that might be available for 

hydrogen. The net availability of methane from raw biogas is 1.9 million tonnes annually, or 

about 509,000 tonnes of hydrogen. The net availability is about 17% less than the total potential. 

The actual total potential and net availability could be higher, as only about half the sites in the 

data analyzed included wastewater flow data needed to make the calculations. 

The total U.S. potential and net availability in the top 20 counties can be seen in Table 1. These 

counties represent just over one quarter of the U.S. total potential, but less than 3% of the 

number of sites. Large sites dominate the top counties.

The size of the WWTP can vary greatly depending on the community it serves. The economic 

viability of the sites may depend on the wastewater throughput of a facility as well as how it 

processes the waste [13-15]. A distribution plot of the WWTPs considered in this analysis is 

shown in Figure 1. Fewer than 10% of the sites have capacities greater than 80 tonnes of 

hydrogen annually. The 146 sites with CHP projects, which were excluded from the WWTP net 

availability, have an average size of 750 tonnes of hydrogen annually. Therefore, the great 

majority of WWTPs are significantly smaller. The mean for all sites was 35.1 tonnes of 

hydrogen or 29.2 tonnes for net sites only. The median value was about 2.9 tonnes of hydrogen 

for both total and net sites. Understanding how to make smaller facilities economically viable for 

production of methane, biomethane, or hydrogen is a key to utilizing their potential. 

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5 

The nature of WWTPs is such that they are clustered around population centers. Figure 2 shows 

the point locations of the WWTPs in the United States and their relative capacity of methane and 

hydrogen production. 

Table 1. Hydrogen Potential from WWTPs for the United States and the Top 20 Counties 

County Population 

(2010 

Census) [16]

Total 

Hydrogen 

Potential 

(tonnes) 

Number of 

Sites (total)

Net 

Hydrogen 

Availability 

(tonnes) 

Number of 

Sites (net)

U.S. (all counties) 308,747,508 617,700 17,573 508,900 17,427

Cook IL 5,194,675 23,900 9 9,800 8

Los Angeles CA 9,818,605 15,500 28 10,000 23

Wayne MI 1,820,584 12,800 6 12,800 6

Harris TX 4,092,459 9,900 253 9,900 253

Clark NV 1,951,269 8,800 16 8,800 16

Essex NJ 783,969 8,400 5 200 4

Kings NY 2,504,700 8,100 6 4,400 3

Maricopa AZ 3,817,117 7,900 58 7,900 58

King WA 1,931,249 7,500 15 900 13

Dallas TX 2,368,139 6,900 8 5,200 7

Suffolk MA 722,023 6,700 1 0 0

Philadelphia PA 1,526,006 6,100 3 3,700 2

Orange CA 3,010,232 5,900 13 3,500 11

Cuyahoga OH 1,280,122 5,400 21 5,400 21

Miami-Dade FL 2,496,435 5,200 5 2,000 3

San Diego CA 3,095,313 5,200 34 3,800 29

New York NY 1,585,873 5,200 2 5,200 2

St. Louis MO 998,954 4,900 7 4,900 7

Queens NY 2,230,722 4,400 5 4,400 5

District of 

Columbia DC

601,723 4,300 1 4,300 1

Figure 1. Distribution of WWTPs by hydrogen potential

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6 

Figure 2. Methane and hydrogen potential from WWTPs by point source location

3.2 Landfills

Landfills are designated locations for disposal of waste, such as product packaging, food scraps, 

bottles, furniture, appliances, and yard clippings. The waste can come from residential, 

industrial, or commercial entities. The quantity of trash that ends up in landfills can vary based 

on reuse, composting, and recycling patterns. In 2011, the United States generated approximately 

250 million tons of garbage and recycled or composted approximately 87 million tons [17]. The 

biogas from landfills is generally called landfill gas (LFG) due to the digestion process taking 

place in the ground rather than in an anaerobic digester.

3.2.1 Methodology

The potential of a landfill to generate methane is mainly dependent on the amount of waste in 

place (WIP), the length of time the waste has been in situ, and the climate of the location (arid 

versus non-arid). The data used in this analysis were provided by the EPA’s Landfill Methane 

Outreach Program (LMOP), which is designed to minimize emissions from landfills and 

encourage best practices for dealing with the waste [18]. The LMOP’s database as of October 

2012 contains approximately 2,400 records of landfills in the United States and its major 

territories. About 600 of these locations have existing LFG-to-energy projects. The remaining 

sites are designated as candidates for LFG-to-energy projects, potential locations for such 

projects, or shut-down sites. The total potential for methane from LFG is estimated at a county 

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7 

level only due to data gaps, and it is based on the total amount of WIP in a recorded year and 

using the LMOP’s Interactive Conversion Tool.4

 The methodology for estimating the net 

availability is described below using only candidate sites from the database.

The net methane potential is based upon candidate sites that the EPA has identified for their 

strong energy project potential [19]. The criteria for these candidate landfills include not having 

an existing or planned energy project, having at least 1 million tons of WIP, and actively 

accepting waste or having been closed for less than 5 years. The LMOP identifies these criteria 

as strong indicators for an economically successful landfill energy project. This analysis used 

495 candidate landfills for the net methane potential, of which only 321 had all the requisite data 

for the calculations. In the results, the hydrogen potentials include a reduction of the methane 

from purification of the biogas and conversion by SMR as discussed in Section 2. 

The LFG generated is not a steady quantity over time; it will ramp up over years to a peak then 

slowly decline. It is also affected by whether the site is closed or new waste is being accepted. A 

first-order decay equation is sometimes used to approximate output in a given year. However, 

this analysis estimates the annual potential of methane from a simplified calculation of 300 

standard cubic feet (scf) per minute of LFG per 1 million tons of WIP, and it assumes that the 

LFG is composed of 50% methane by volume [20]. For open candidate landfills, the WIP data 

are normalized to the year 2012 by taking the WIP in the recorded year, different for each record, 

and adding additional years of waste based upon the annual waste acceptance rate of the site up 

to the year 2012. For closed candidate landfills, the WIP was calculated similarly to the open 

landfills, but additional years of waste are only added up to the year the site closed. Only 

candidate landfills closed within the last five years were included in this analysis. The annual 

methane potential is then calculated as shown in Equation 4. 

Equation 4. Annual methane potential for landfills 

annual methane potential

= WIP ∗

300 scfm LFG

1 MM tons WIP ∗

50% CH4

LFG ∗

0.0423 lb

min �

1 scfm ∗

525,600 min

yr ∗ 1 ton2204.62 lb

where WIP is million tons of waste in 2012 for open landfills and for the year closed for closed 

landfills.

3.2.2 Potential

Landfills, in this study, represent the largest potential source of methane and hydrogen from both 

a total perspective as well as the current net availability. The total potential is approximately 10.6 

million tonnes of methane in raw biogas annually, or, if converted to hydrogen, about 2.8 million 

tonnes of hydrogen. The net potential of landfills, based upon candidate sites that meet the 

criteria listed above, is 2.5 million tonnes of methane annually or 648,000 tonnes of hydrogen if 

converted. This net availability could be a conservative estimate because it does not include sites 

listed by the EPA as “potential” or “other,” some of which might make feasible projects. As 

shown in Table 2, the top 20 counties in the United States account for more than 30% of the net 

availability but less than 10% of the number of sites. 

 

4 http://www.epa.gov/lmop/projects-candidates/interactive.html

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8 

Table 2. Hydrogen Potential from Landfills in Top 20 U.S. Counties

County Population (2010 

Census) [16]

Net Hydrogen Availability 

(tonnes) 

Number of Sites 

(net)

U.S. (all counties) 308,747,508 648,200 321a

Los Angeles CA 9,818,605 27,400 3

Orange CA 3,010,232 19,000 1

Livingston IL 38,950 16,500 1

Stanislaus CA 514,453 13,700 1

Alameda CA 1,510,271 13,000 2

Maricopa AZ 3,817,117 12,900 2

Okeechobee FL 39,996 11,700 1

Stark OH 375,586 9,500 1

Ogle IL 53,497 9,200 1

Pinellas FL 916,542 8,000 1

Kings CA 152,982 7,600 1

Nueces TX 340,223 7,500 1

Jefferson AL 658,466 7,400 2

Brazoria TX 313,166 6,900 1

Wayne MI 1,820,584 6,800 1

Ascension LA 107,215 6,300 1

Butts GA 23,655 6,100 1

Gregg TX 121,730 5,700 1

Miami-Dade FL 2,496,435 5,400 1

Jefferson TX 252,273 5,200 3

a Out of 495 candidate sites, only 321 included all requisite data needed for calculation. 

The size distribution of candidate sites tends to be less than 6,300 tonnes of hydrogen annually 

with only 5% of the sites analyzed larger than that, as shown in Figure 3. However, there are 

some large available candidate sites, the largest of which has a potential of 21,800 tonnes of 

hydrogen annually. The mean site capacity was much smaller, at only 2,000 tonnes of hydrogen, 

and the median site capacity was 1,300 tonnes of hydrogen annually. Just fewer than 48% of 

sites fall into the range of 315 to 1,260 tonnes of hydrogen annually, making those smaller sites 

an important category to tap into.

The geographic distribution of the candidate landfills, which represents the net availability of 

methane, is shown in Figure 4. Landfills tend to be clustered around populated areas, making 

them more economically viable sources of renewable hydrogen (compared to wind, for example) 

due to the relatively short distances required for hydrogen delivery. 

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9 

Figure 3. Distribution of landfill sites by hydrogen potential

Figure 4. Available methane and hydrogen potential from landfills by point source location

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3.3 Animal Manure

Animal manure can be a good source of organic matter for use in anaerobic digestion. However, 

the most practical manure management systems for anaerobic digestion are those in which the 

manure is stored in liquid or slurry forms with little non-digestible bedding mixed in [21]. Other 

management systems may work, but will not be as successful. In this analysis, we consider three 

animal types that have been identified as generally having manure management systems well 

suited to anaerobic digestion: milk cows, hogs, and broiler chickens. 

3.3.1 Methodology

The U.S. Department of Agriculture’s most recent (2007) Census of Agriculture includes data on 

the number of animals by county [22]. Because the data are provided at the county level, the 

assessment results are also limited to the county level, unlike the point source results above for 

WWTPs and landfills.

The following steps were used to calculate methane emissions from manure management 

systems, based on a 1995 EPA state workbook on the subject [23]. 

Step 1: Annual production of volatile solids by each animal type 

The following equation was used to calculate pounds of volatile solids produced by each animal 

type using numbers for the typical animal mass and annual volatile solids shown in Equation 5. 

Tables for the typical animal mass can be found in the EPA workbook [23]. 

Equation 5. Volatile solids produced by animal type 

VSi = Animal Populationi(head) ∗ TAMi ∗ vsi

where:

VSi = total volatile solids produced [lb/yr] for animal type i 

TAMi = typical animal mass for animal type i [lb/head]

vsi = average annual volatile solids production per unit of animal mass of animal type i

[lb VS/lb animal mass/yr]

Step 2: Methane emissions for each manure management system and animal type

The methane emissions were calculated using the solution to Equation 5 for total volatile solids

along with additional data found from Equation 6. 

Equation 6. Methane emissions for each animal type and manure management system

CH4 emissions for each animal i in system j �

ft3

yr � = VSi ∗ Bo,i ∗ MCFj ∗ WS%i,j

where:

VSi = total volatile solids produced per year by animal type i (Equation 5) [lb/yr]

Bo,i = maximum methane producing capacity per lb VS for animal i [ft3/lb VS]

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11 

MCFj = methane conversion factor for each manure management system j [%]

WS%i,j = percent of animal i’s manure managed in manure management system j [%]

Tables for MCF and WS% are found in the EPA workbook [23]. 

Step 3: Summation across animal types and manure management systems and conversion 

to tonnes of methane

The methane emissions are summed across the different animal types and manure management 

systems and then converted to tonnes using Equation 7. 

Equation 7. Summation of methane across animal types and manure management systems

Total CH4 [tonnes] = �CH4 i,j ∗ ρ ∗

tonne

2205 lb

where:

CH4 i,j = methane emissions for each animal type i in manure management system j 

[ft3

/yr]

ρ = density of methane [0.0413 lb/ft3

] 

The results of Step 3 provide the total methane potential for animal manure. The large majority 

of the methane that can be captured comes from liquid and liquid slurry manure management 

systems.

Step 4: Hydrogen potential 

In the results, the hydrogen potentials include a reduction of the methane from purification of the 

biogas and conversion by SMR as discussed in Section 2. 

3.3.2 Potential

Animal manure is a more dispersed resource found in rural areas tending toward more, smaller 

sites than WWTPs and landfills. However, it can be a significant source of biogas if some of the 

economic issues around collection and aggregation can be overcome. The total methane potential 

in raw biogas from the three types of animal studied (dairy cows, hogs, and broiler chickens) is 

estimated at 1.9 million tonnes annually, which, if converted to hydrogen, would be about 

503,000 tonnes of hydrogen. Existing digesters capture about 63,000 tonnes of methane, 

reducing the net availability to about 1.8 million tonnes of methane or 486,000 tonnes of 

hydrogen [24]. The total potential of the top counties in the United States is shown in Table 3. 

The top 20 counties represent almost 32% of the U.S. total potential and could be a source of 

hydrogen for bridging transportation corridors between major metropolitan areas and bringing 

economic opportunities for rural areas.

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12 

Table 3. Hydrogen Potential from Animal Manure for the United States and in the Top 20 U.S. 

Counties 

County Population (2010 Census) [16] Total Hydrogen Potential 

(tonnes) 

U.S. (all counties) 308,747,508 503,100

Tulare CA 442,179 21,700

Duplin NC 58,505 18,000

Sampson NC 63,431 16,900

Merced CA 255,793 12,500

Stanislaus CA 514,453 9,300

Texas OK 20,640 8,000

Kings CA 152,982 7,500

Chaves NM 65,645 6,400

Bladen NC 35,190 6,400

Kern CA 839,631 5,700

Fresno CA 930,450 5,600

Maricopa AZ 3,817,117 5,300

San Bernardino CA 2,035,210 5,000

San Joaquin CA 685,306 5,000

Curry NM 48,376 4,800

Roosevelt NM 19,846 4,600

Wayne NC 122,623 4,200

Dona Ana NM 209,233 4,000

Pinal AZ 375,770 3,700

Yakima WA 243,231 3,700

Due to a lack of data, the distribution of individual farms cannot be illustrated as in the WWTP 

and landfills analyses. The results are shown by county (Figure 5). Farm sizes can vary by 

region, but as an example, data taken in the Central Valley of California found that most dairy 

farms have 199 to 699 cows [25]. In this example, the economic feasibility of anaerobic 

digestion at dairy farms with fewer than 1,000 cows might hinge on air and water regulations as 

well as other technical factors.

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13 

Figure 5. Total methane and hydrogen potential from animal manure in the United States by 

county 

3.4 Industrial, Institutional, and Commercial

The resource potential of IIC sources of organic waste represents a new analysis not based upon 

previous work. This analysis uses data from the U.S. Census Bureau’s County Business Patterns 

[26] and the Homeland Security Infrastructure Program (HSIP) [27]. Data from the U.S. Census 

Bureau includes food manufacturing and wholesalers such as fruit and vegetable canneries; dairy 

creameries (milk, cheese, yogurt, ice cream, butter); vineyards; meat packing and processors; 

slaughterhouses; coffee and tea production; breweries and distilleries; bakeries; and soft drink 

bottling plants, as well as organic waste facilities such as supermarkets, restaurants, and hotels. 

Data from the HSIP include primarily institutional facilities, namely hospitals, nursing homes, 

education facilities (universities, colleges, schools), and correctional facilities.

3.4.1 Methodology

Data on the number of businesses and employees in each county were obtained from the County 

Business Patterns; data on the number of beds, students, and inmates at each location were

gathered from the HSIP and further aggregated to the county level for consistency. Then, a ratio 

of food disposed per employee, bed, student, or inmate was applied to estimate the amount of 

organic waste by county (Table 4). Assuming that biogas yield is 5,000 standard cubic feet per 

ton of organic waste and that the composition of biogas from organic waste is 60% methane and 

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14 

40% carbon dioxide, we estimate the methane potential by anaerobic digestion of organic waste

[28]. The hydrogen potentials include a reduction of the methane from purification of the biogas 

and conversion by SMR as discussed in Section 2. 

Table 4. Methodology for Estimating Organic Waste from IIC Sources [29]

Business

NAICS code SIC code

Food Disposed 

(tons/year)

Food and beverage 

manufacturing

311/// and 3121// 20 0.41 per employee

Food wholesalers/ 

distributors

4244//, 4245//, and 

4248//

51 0.4 per employee

Supermarkets, food 

stores

445/// 54 1.25 per employee

Restaurants 722/// 58 1.1 per employee

Hotels/motels 7211// 70 0.18 per employee

Hospitals N/A (HSIP) N/A (HSIP) 0.62 per bed 

Nursing homes N/A (HSIP) N/A (HSIP) 0.33 per bed

Colleges, universities, 

schools, and day cares

N/A (HSIP) N/A (HSIP) 0.05 per student

Correctional facilities 

(prisons)

N/A (HSIP) N/A (HSIP) 0.18 per inmate

N/A = not available

NAICS = North American Industry Classification System

SIC = Standard Industrial Classification

3.4.2 Potential

The total potential from IIC sources is slightly less than from the other biogas sources examined, 

yet it still represents a significant source of methane and hydrogen. In this new analysis, only 

total potential is calculated. Estimating the net availability fell beyond the scope of this study but 

could make a valuable follow-up study. The total methane potential in raw biogas from IIC 

sources is estimated at 1.2 million tonnes annually, or 306,000 tonnes of hydrogen. 

The top 20 counties are shown in Table 5. These counties represent almost 20% of the total 

potential. The geographic distribution within the United States by county is shown in Figure 6. 

The geographic distribution tends to be close to population centers, making it another good 

resource for hydrogen vehicle introduction. 

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15 

Table 5. Hydrogen Potential from IIC Sources in the Top 20 U.S. Counties

Figure 6. Methane and hydrogen potential from IIC sources in the United States by county

County Population (2010 Census)

[16] 

Total Hydrogen Potential 

(tonnes) 

U.S. (all counties) 308,747,508 305,700

Los Angeles CA 9,818,605 9,800

Cook IL 5,194,675 5,400

Harris TX 4,092,459 4,400

Maricopa AZ 3,817,117 4,300

New York NY 1,585,873 3,500

Orange CA 3,010,232 3,400

San Diego CA 3,095,313 3,300

Dallas TX 2,368,139 2,700

Clark NV 1,951,269 2,500

Miami-Dade FL 2,496,435 2,500

King WA 1,931,249 2,300

Tarrant TX 1,809,034 2,000

Santa Clara CA 1,781,642 1,800

Broward FL 1,748,066 1,800

Bexar TX 1,714,773 1,800

Riverside CA 2,189,641 1,800

Middlesex MA 1,503,085 1,700

San Bernardino CA 2,035,210 1,700

Allegheny PA 1,223,348 1,600

Philadelphia PA 1,526,006 1,600

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16 

4 Vehicles Supported by Renewable Hydrogen

One area in which there is interest in renewable hydrogen from biogas is as a fuel for FCEVs. 

The transportation sector is the largest consumer of petroleum products and second only to the 

electric power sector in greenhouse gas emissions [30]. Therefore, from energy security and 

environmental perspectives, it is of interest to displace some of that petroleum demand with 

domestic renewable fuels such as hydrogen from biogas. 

The number of FCEVs potentially supported by renewable hydrogen from biogas was estimated 

by assuming an average FCEV fuel economy and average annual miles travelled per vehicle. We 

have used the 2020 medium case from a U.S. Department of Energy report on future light-duty 

vehicles to make these estimates [31]. The medium case is a mid-optimistic scenario with respect 

to vehicle fuel economy. Based upon this source, an FCEV with fuel economy of 56.5 miles per 

gasoline gallon equivalent (gge) and annual travel of 10,000 miles per year is used to calculate 

the annual number of FCEVs supported. The results shown in Figure 7 and Table 6 are based on 

the assumption that 1 gge is equal to 1 kg of hydrogen. The total vehicles supported from all 

biogas sources are about 11 million FCEVs annually with landfills accounting for more than a 

third of that at 3.7 million FCEVs annually.

* IIC is total potential.

 Figure 7. The number of FCEVs supported by biogas source, utilizing the net availability of the 

biogas source (with the exception of IIC)

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17 

Table 6. FCEVs Supported and Percentage of U.S. Fleet by Biogas Source, Utilizing the Net 

Availability of the Biogas Source (with the Exception of IIC)

Biogas Source FCEVs Supported

(millions)

Percentage of 2010 U.S. LightDuty Fleet 

WWTPs 2.9 1%

Landfills 3.7 2%

Animal Manure 2.7 1%

IIC a 1.7 1%

Total 11.0 5% a IIC is total potential. 

To put these numbers of vehicles in perspective, these values were also compared to the lightduty vehicle fleet as of 2010 to demonstrate the impact this would have on the total vehicle fleet. 

The vehicle registrations in 2010 for cars and light-duty trucks (two axles, four tires) were 

approximated at 131 million and 99.5 million respectively, or about 230 million light-duty 

vehicles in the 2010 U.S. fleet [32]. The comparison to the 2010 U.S. light-duty fleet is shown in 

Table 6. Hydrogen from biogas could support about 5% of the 2010 light-duty vehicle fleet if 

those vehicles were replaced with FCEVs. This estimate accounts for only the net availability of 

methane in the biogas sources, except for IIC sources, in which only the total potential was 

estimated. The real potential from other sources (WWTP, landfills, and animal manure) could be 

higher as discussed in the respective resource assessments and the overview analysis below.

5 Discussion

This section discusses the sensitivities of sources and examines the combined resource potential 

of the United States as well as select regions of interest. These analyses further aggregate the 

information and provide more detail, thus helping to inform strategies for development of the 

diverse biogas sources.

5.1 Resource Sensitivities

Biogas is a variable resource and the resource estimate is only approximate. To highlight this, 

approximate ranges for the different sources were used to indicate some of the uncertainty in 

calculating an annual estimate.

Ranges were used to calculate high and low amounts from the base default methane potential. 

Estimates of the methane content in the biogas produced were used for WWTPs and landfills of 

65% and 50% by volume, respectively. However, the methane content of the biogas can and does 

vary from site to site, based on the content of the waste, as well as within a site annually, due to 

climate-related factors. Table 7 shows the default values as well as high and low methane content 

of the biogas produced by volume. For animal manure and IIC sources of biogas, a sensitivity 

range was more difficult to identify, so an uncertainty range for methane of ±10% was used. 

Figure 8 shows the relative capacity of the different renewable hydrogen sources along with the 

uncertainty ranges described in Table 7. 

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18 

Table 7. Range of Methane Content in Biogas 

Source Default Methane 

Content of Biogas 

by Volume

High Low Reference

WWTPs 65% 70% (CH4 by 

volume)

55% (CH4 by 

volume)

[33]

Landfills 50% 60% (CH4 by 

volume)

40% (CH4 by 

volume)

[34]

Animal Manure Calculates methane, 

not biogas

+10% -10%

IIC 60% +10% -10%

* IIC uses total potential, no net availability identified.

Figure 8. Relative intensity and range of hydrogen potential from biogas sources

5.2 U.S. National Methane and Hydrogen Potential

The U.S. total methane potential in raw biogas from the sources examined is almost 16 million 

tonnes, but the net availability calculated is about 6.2 million tonnes. The net availability 

excludes IIC sources for which net availability was not calculated. For comparison, the 2013 

U.S. natural gas consumption was almost 573 million tonnes [35]. If the methane is converted to 

hydrogen, it represents a total potential of 4.2 million tonnes and a net potential of 1.6 million 

tonnes. These are only rough estimates due to a variety of reasons. The data used for WWTPs are 

missing significant amounts of information that would be needed for a full assessment: only 

about half the sites included the necessary fields. The landfill data also have discrepancies that 

make higher totals possible. The LMOP database may have additional sites capable of supporting 

feasible energy projects that are not included in candidate sites. Although some of the estimates 

are uncertain and based upon limited data, it appears that there is significant biogas resource 

potential. Table 8 shows the U.S. total potential and net availability rounded to the nearest 

thousand tonne for methane and hydrogen if converted from that methane. Landfills, in this 

study, represent by far the largest total resource, and even when the net availability from 

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19 

candidate sites only is taken into account, the landfill potential is larger than that of the other 

resource types. WWTPs, landfills, and IIC sources all tend to be clustered around population 

centers. If production logistics and diseconomies of scale due to dispersed locations can be 

overcome, the delivery of hydrogen to demand centers may have lower costs than that for other 

renewable sources, such as wind or solar. Animal manure is more prevalent in rural areas but 

could bring economic opportunities for export to more populated areas or supply hydrogen 

stations located along interstates.

A map of the combined resources in the United States is shown in Figure 9. This overview 

resource map is useful in helping to understand the distribution and possible challenges that may 

be found in developing biogas resources. The geographic distribution and the resource quantities 

are important in helping to inform strategy and policies that may support future development. 

Table 8. U.S. Methane and Hydrogen Potentials by Source

Source Methane Potential

(thousand tonnes/yr)

Hydrogen Potential

(thousand tonnes/yr)

Total Available Total Available

WWTPsa 2,339 1,927 618 509

Landfillsb 10,586 2,455 2,795 648

Animal manurec 1,905 1,842 503 486

IIC organic waste 1,158 N/A 306 N/A

Total 15,988 6,224 4,221 1,643

a Total potential for WWTPs is higher, given that the analysis was done for only half of the WWTPs in the country 

(water flow data for the rest is missing). b Total potential for landfills could be higher given that the estimate accounts for only the WIP recorded for a given 

year and does not take into account additional waste that may have come in since the record was taken (as it was 

done for the “available potential” estimate). It is an approximate value. Available potential for landfills is estimated 

using candidate landfills only. Available potential could be higher if we include "other" and "potential" landfills.

c Existing digesters (dairy, poultry, and swine) capture about 62,942 tonnes/yr [24]. 

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20 

Figure 9. Methane and hydrogen potential from combined biogas sources in the United States by 

county 

5.3 Comparison to Previous Study

The current analysis updates and expands the biogas resource assessment and hydrogen potential 

estimates in a 2006 study by Milbrandt and Mann [3]. New data availability and calculation 

methods have been used to create better estimates of both the methane potential and the 

hydrogen conversion. The refinements to the assessment process make a direct comparison of the 

results difficult, but the differences are highlighted below to examine the changes and updates. 

The methodology for calculating the methane potential of each resource was refined in various 

ways. In the previous study, methane from WWTPs was not calculated at specific sites as it is 

here; it used census data and the biochemical oxygen demand (BOD) per capita in its estimate. 

This analysis uses EPA’s 2008 Clean Watersheds Needs Survey database of actual WWTPs and 

their waste flow for a better estimate of the methane potential [8]. Landfill estimates were 

updated with new data from the EPA’s LMOP database and the methane potential calculation 

was refined with guidance from the EPA. The animal manure assessment was updated from 2002 

data to 2007 data from the U.S. Department of Agriculture Census of Agriculture. The manure 

estimates were also refined to only include milk cows, hogs, and broiler chickens; the previous 

assessment also included beef cows, sheep, layer chickens, and turkeys. This change was made 

due to subsequent research that deemed the other animal manure types somewhat less suitable 

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21 

for anaerobic digestion due to either lower resource availability, less-suitable material, or 

generally practiced manure management systems that aren’t amenable to anaerobic digestion. 

This, of course, does not mean that farms raising these animals could not be successful at 

anaerobic digestion applications. It only means that their contribution to the methane and 

hydrogen potential at a national level is relatively small, but they could still play a major role at 

local levels. Changes were also made regarding the methane conversion to hydrogen. In the 

previous study a conversion factor of 2.34 kg CH4/kg H2 was used, 85% of the stoichiometric 

maximum efficiency for SMR. This analysis assumes there is a 13% loss of methane during the 

purification process (see Section 2). Additionally the hydrogen conversion factor of 3.295 kg 

CH4/kg H2 is used based upon an updated SMR case study from DOE’s H2A Production model 

[7]. These changes have lowered the expected hydrogen output from the different methane 

resources.

All these modifications were made to reflect the current understanding of the systems being 

assessed and to use better quality data where possible, but they result in assessments that are not 

directly comparable. Table 9 reviews the estimates made in the two studies.

Table 9. Review of Previous Study

Milbrandt and Mann (2006) Saur and Milbrandt (2013)

Sourcea

Methane Potential

Total (thousand 

tonnes/yr)

Hydrogen Potential

Total (thousand 

tonnes/yr)

Methane Potential

Total (thousand 

tonnes/yr)

Hydrogen Potential

Total (thousand 

tonnes/yr)

WWTP 500 200 2,339 618

Landfills 12,400 5,300 10,586 2,795

Animal 

manure 2,200 900 1,905 503

a Only total potential is shown since the previous study did not include net availability.

5.4 Select U.S. Local Regions

The methane and hydrogen capacities on a national level are useful, but understanding the 

distribution of resources on a local level can help characterize challenges and opportunities for 

different communities. To this end, examples of local maps have been developed for two areas: 

Northern California and Boston, Massachusetts. Relying upon a renewable source of hydrogen 

would help highlight the clean car profile of FCEVs during early market introduction, and the 

state of California already has requirements for renewable hydrogen production. However, 

development of these biogas resources has challenges that may be unique for any given region, 

state, or urban area. State and local policies, rapport with local utilities, and the favor of local 

sources and stakeholders will all factor into successful project investment and resource 

development. Understanding a local region’s resources is one step toward a better understanding 

of policies or initiatives that may spur development of renewable hydrogen biogas projects. 

5.4.1 Northern California

California has been a leader in the United States in developing hydrogen infrastructure in 

preparation for the 2015–2017 commercial rollout of FCEVs. There are state and local policies, 

such as the Zero Emissions Vehicle mandate and energy and environmental standards for 

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22 

hydrogen production (SB 1505), which regulate vehicle sales and emissions, as well as hydrogen 

production, including renewable hydrogen. California has done a lot of work developing clean 

energy policies that will foster its clean air and environmental goals [36, 37]. A map of Northern 

California (Figure 10) shows good hydrogen potential from all the biogas sources examined in 

this report. 

Figure 10. Net (as available) hydrogen potential from biogas in Northern California

The Northern California area shown in Figure 10 has 41 counties with biogas resource potential. 

The total potential for this region is about 93,300 tonnes of hydrogen annually, which could 

support almost 527,300 FCEVs. The totals and breakdown by biogas source are shown in Table 

10. A breakdown of the hydrogen potential from all biogas sources for the top 20 counties in 

Northern California is shown in Table 11. Almost three quarters of this comes from animal 

manure and landfill sources in the region, 34,500 and 34,700 tonnes of hydrogen annually, 

respectively.

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23 

Table 10. Net (As Available) Hydrogen Potential By Biogas Source in Northern California

Source Hydrogen 

Potential (tonnes)

FCEVs Supported 

(thousands)

Counties Sites

WWTPs 11,800 66.8 39 251

Landfills 34,700 196.2 5 7

Animal Manure 34,500 194.9 29 a

IIC b 12,300 69.4 34 a

Total 93,300 527.3 41

a Individual sites not counted, data at county level. b Total IIC potential. 

Table 11. Net (As Available) Hydrogen Potential of Top 20 Counties in Northern California

County Population (2010 

Census) [16]

Hydrogen Potential 

(tonnes)

FCEVs Supported 

(thousands)

Total Region 14,536,321 93,300 527.3

Stanislaus CA 514,453 24,200 136.9

Alameda CA 1,510,271 15,600 88.3

Merced CA 255,793 15,000 84.9

San Joaquin CA 685,306 9,400 53.0

Sacramento CA 1,418,788 4,900 27.8

Santa Clara CA 1,781,642 4,900 27.5

Madera CA 150,865 3,600 20.6

Contra Costa CA 1,049,025 2,600 14.7

Sonoma CA 483,878 2,100 12.1

San Mateo CA 718,451 1,700 9.5

San Francisco CA 805,235 1,300 7.4

Glenn CA 28,122 1,100 6.1

Marin CA 252,409 1,100 5.9

Placer CA 348,432 1,000 5.6

Solano CA 413,344 1,000 5.8

Yolo CA 200,849 600 3.3

Butte CA 220,000 500 2.6

Napa CA 136,484 500 2.7

El Dorado CA 181,058 300 2.0

Mendocino CA 87,841 300 1.5

5.4.2 Boston, Massachusetts

The Boston urban area is a promising candidate for FCEV market expansion on the East Coast 

due to the relatively high historical demand for novel vehicle technologies, such as hybrid 

electric vehicles, and the manageable logistics of planning for hydrogen infrastructure 

development (compared to the New York region, for example, which is a larger overall market 

but more challenging logistically).

A map of the Boston area is shown in Figure 11. Landfills show a lower prevalence than 

expected due to several in the area having existing energy projects that make them unavailable 

for renewable hydrogen production from LFG. However, the population centers have availability 

in WWTPs, and the immediate Boston area has good amounts of IIC source availability. Biogas 

from animal manure may not be the first resource developed due to the relatively low and 

dispersed sources. Overall, Boston shows a little less potential from biogas than the Sacramento 

area, but there are still significant sources that could be targeted with the right types of policies 

and incentives.

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24 

Figure 11. Net (as available) hydrogen potential from biogas in Boston, Massachusetts

The Boston region has about 33,000 tonnes of net (as available from the analysis) hydrogen 

potential annually, which could support approximately 186,700 FCEVs. Table 12 shows the 

breakdown by biogas source for the Boston region, and Table 13 shows the total potential of the 

top 20 counties in the area. More than 85% of the potential comes from WWTP and IIC biogas 

sources, both situated close to urban areas. Animal manure is not a big source for the area and is 

relatively spread out, making it less useful for vehicle infrastructure. The methane from manure 

could be better used in niche applications, such as on-site generation, if it is developed. 

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25 

Table 12. Net (As Available) Hydrogen Potential By Biogas Source in the Boston Region 

Hydrogen 

Potential (tonnes)

FCEVs Supported

(thousands)

Counties Sites

WWTPs 15,400 86,700 38 283

Landfills 4,400 24,700 5 5

Animal Manure 500 2,800 37 a

IIC b 12,800 72,500 41 a

Total 33,000 186,700 41

a Individual sites not counted, data at county level. b Total IIC potential. 

Table 13. Net (As Available) Hydrogen Potential of Top 20 Counties in the Boston Region

County Population (2010 

Census) [16]

Hydrogen Potential 

(tonnes)

FCEVs Supported 

(thousands)

Boston Region 11,966,888 33,000 186.7

Hartford CT 894,014 3,800 21.3

Hampden MA 463,490 3,500 19.7

Essex MA 743,159 2,700 15.1

Providence RI 626,667 2,500 14.2

Middlesex MA 1,503,077 2,400 13.4

Worcester MA 798,552 2,400 13.4

Bristol MA 548,285 2,100 11.9

Barnstable MA 215,888 1,500 8.4

Hampshire MA 158,080 1,100 6.2

Suffolk MA 722,023 1,100 6.4

Norfolk MA 670,850 900 4.9

Hillsborough NH 400,721 800 4.6

Plymouth MA 494,919 800 4.4

New Haven CT 862,477 800 4.6

Middlesex CT 165,676 500 2.9

Rockingham NH 295,223 500 2.9

York ME 197,131 500 3.0

Berkshire MA 131,219 400 2.4

Kent RI 166,158 400 2.5

Merrimack NH 146,445 400 2.1

6 Biogas Purification Challenges

In this analysis of hydrogen production potentials from biogas resources, we have estimated 

upgraded biogas, or biomethane, available after treating biogas through a process sometimes 

referred to as purification or sweetening, resulting in a natural-gas-quality product [9, 38]. The 

energy content of untreated biogas is approximately 600–800 Btu/ft3, which is significantly 

lower than that of natural gas, which ranges from approximately 950–1,050 Btu/ft3. Biomethane 

can be used relatively interchangeably with natural gas and as an alternative feedstock for the 

SMR process to make hydrogen, as well as other applications. 

The contaminants in untreated biogas pose several challenges for its use. There are applications 

in which the lower-energy-content biogas can be used, usually on site, such as in an internal 

combustion engine, gas boiler, or even certain fuel cells such as molten carbonate fuel cells or 

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26 

solid oxide fuel cells [25, 39-41]. These applications may be able to use minimally treated biogas 

where some of the worst contaminants are removed but the gas has not been purified to natural 

gas quality. This could be more economically viable at smaller sites or where the heat and 

electricity can be used on site. These applications will compete with other uses of the biogas that 

require natural-gas-quality biomethane, such as other kinds of electricity generation technologies 

and use in compressed natural gas vehicles or in FCEVs when converted to hydrogen. 

For this analysis, we considered upgraded biomethane as a renewable substitute for natural gas, 

making it more easily integrated with some of the current infrastructure of natural gas pipelines 

and natural gas vehicle refueling stations [42, 43]. The resource and infrastructure could be 

developed as one component within a larger alternative fuel infrastructure supporting FCEVs as 

well as compressed natural gas vehicles for a larger mass market of sustainable transportation 

fuels. An important factor in developing biogas for a larger mass market, rather than in niche 

areas, is that it can be upgraded to biomethane and easily incorporated into existing 

infrastructure.

Contaminants in biogas are a challenge for its integration into the natural gas infrastructure and 

account for some of the resistance by gas utilities to injection of biomethane into pipelines. Raw 

biogas is composed mainly of methane (CH4) and carbon dioxide (CO2) and is saturated with 

water (H2O). However, it also contains a corrosive contaminant, hydrogen sulfide (H2S), as well 

as oxygen (O2), nitrogen (N2), mercaptan sulfur, and sulfur (S) that are of interest to natural gas 

suppliers. Some biogas sources have other contaminant issues, such as siloxanes, in addition to 

those listed above [9, 39, 43, 44]. Siloxanes are organosilicons, and they are present in many 

consumer products, which then get into biogas from WWTPs and landfills. When combusted, 

siloxanes can be converted into silicon dioxide (SiO2), similar to sand, which can damage 

engines, turbines, and fuel cells [45-47]. Table 14 shows some of the requirements for 

biomethane injection into natural gas pipelines for two California utilities; many gas utilities 

disallow biomethane completely [25, 39, 48-51]. 

Table 14. Biomethane Quality Requirements for Injection into Natural Gas Pipelines [25, 39, 48-51]

Gas Quality PG&E SoCalGas

CO2 ≤1% ≤3%

O2 ≤0.1% ≤0.2%

H2S ≤0.25 grains/100 scf (4 ppm) ≤0.25 grains/100 scf

Mercaptan sulfur ≤0.5 grains/100 scf (8 ppm) ≤0.3 grains/100 scf

Total sulfur ≤1 grain/100 scf (17 ppm) ≤0.75 grains/100 scf

H2O ≤7 lb/million scf ≤7 lb/million scf

Total inerts No requirement ≤4%

Heating value Specific to receipt point 970–1,150 Btu/scf

Landfill gas Not allowed No requirement

Temperature 60°–100°F 50°–105°F

Gas interchangeability Per AGA Bulletin 36 [52] Per AGA Bulletin 36

Wobbe number Specific to receipt point Specific to receipt point

Lifting index Specific to receipt point Specific to receipt point

Flashback index Specific to receipt point Specific to receipt point

AGA = American Gas Association

ppm = parts per million

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27 

Beyond the specific quality criteria for natural gas, the biogas must also be free of pathogens, 

bacteria, and other substances hazardous to people and the environment [25, 36, 37, 39, 49]. In 

general, the anaerobic process kills or reduces the pathogens and bacteria inherent in the organic 

matter if done correctly, but there are other elements that may pose health risks and should be 

accounted for and monitored [36, 37, 53]. A list of other biogas and biomethane constituents of 

concern developed for California regulation AB 1900 is shown in Table 15. 

Table 15. Biogas and Biomethane Constituents of Concern Developed for California AB 1900 [37]

Constituent Landfill WWTP Dairy

Antimony X

Arsenic a X

Copper X

p-Dichlorobenzene a X X

Ethylbenzene a X X X

Hydrogen sulfide X X X

Lead X

Methacrolein X

n-Nitroso-di-npropylamine aX X

Mercaptans (alkyl thiols) X X X

Toluene X X X

Vinyl chloride a X X

a Denotes the chemical is a carcinogen; constituents not indicated by “a” included due to chronic hazard quotient.

Another potential hurdle for the introduction of biomethane into the natural gas infrastructure is 

restriction of injection only to the transmission system, not the smaller distribution system 

pipelines [25]. The production of biogas can fluctuate due to humidity, temperature, and season, 

which can create a pressure problem for distribution pipelines that are not designed to handle the 

extraction pressure differentials. Injection into the transmission system is possible, if more 

expensive, and requires larger purification plants and higher compression. This requirement 

could limit the economic viability of smaller biogas-producing sites unless they can aggregate 

their gas production or supplement their organic matter waste sources with co-digestion of other 

organic matter, both of which have their own technical and regulatory issues [25, 39]. 

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28 

7 Conclusions

Biogas is a relatively dispersed resource. In this report we have examined the total potential and 

net availability from four classifications of organic waste: WWTPs, landfills, animal manure, 

and IIC sources. They each have unique challenges in their potential development. The smaller 

sizes of many plants, farms, and facilities may challenge the economic feasibility of a biogas 

facility. The right policies, incentives, and collaboration with key players are necessary for 

success. Nevertheless, biogas and hydrogen from biogas can have a place in sustainable energy 

futures, but other clean energy technologies will also need to be developed. This analysis 

combines data from multiple databases and agencies (EPA, U.S. Department of Agriculture, and 

U.S. Census Bureau) to show results in a standardized format and analyzed with a consistent 

approach. 

Landfills represent by far the greatest total potential (10.6 million tonnes methane from raw 

biogas or 2.8 million tonnes of hydrogen) and net availability (2.5 million tonnes of methane 

from raw biogas or 648,000 tonnes of hydrogen) even when factored conservatively using only 

LMOP candidate sites. The potential from all sources probably falls somewhere between the 

total potential (16 million tonnes of methane from raw biogas or 4.2 million tonnes of hydrogen) 

and the net availability (6.2 million tonnes of methane from raw biogas or 1.6 million tonnes of 

hydrogen) due to some conservative estimates in the net availability. Net availability excludes 

IIC sources. Many of these sources, such as WWTPs, landfills, and IIC sources, are close to 

population centers, making the delivery costs lower than for rural sources. However, rural 

sources can provide economic opportunities for export or bridging infrastructure along 

interstates.

Reaching the point of economic feasibility for developing these resources has several hurdles. 

The size of many of the sources may make aggregating resources a better option either through 

co-digestion or more centralized cleanup plants that make biomethane (methane of natural-gasquality purity). Contaminants are also a challenge and somewhat unique to each source. While 

comprising a very small portion of the biogas, contaminants must be removed on some level to 

protect equipment using biogas as a fuel or for health and environmental risk factors. For 

injection into the natural gas pipeline network, the biogas must be purified to natural-gas-quality 

biomethane, at which point it can be used relatively interchangeably with natural gas. However, 

there may be resistance by gas utilities to its injection, in general, or the location of injection, in 

particular; the cost of biogas cleanup can also be significant. In addition, there are competing 

applications for the biogas that may affect how it is used. 

Understanding the geographic distribution and size elements of different biogas sources can help 

decision makers to tailor policies and incentives on the federal, state, and local level. Strategies 

for aggregating sources or designing economically viable systems for different capacities will 

help the overall development of the biogas resources. Sacramento and Boston are highlighted to 

show the regional differences. Understanding the geographic elements can help early 

development and pilot projects take advantage of these resources.

Biogas and hydrogen from biogas can aid early FCEV rollout. They are produced from local, 

sustainable resources that can supply upwards of 5% of the current U.S. vehicle fleet if that 

portion were replaced by FCEVs. The transportation sector is second only to the electric sector in 

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29 

greenhouse gas emissions, and renewable hydrogen used in FCEVs can offer environmental 

benefits.

8 Future Work

There are several areas not addressed in this analysis that can be expanded in the future. Other 

sources of organic waste exist that could be used to produce biogas, for example lipids (fats, oils, 

and grease). Additionally, lignocellulosic biomass (e.g., crop and forest residues or dedicated 

energy crops) could be used to produce biogas via anaerobic digestion (dry fermentation, codigestion) or through thermo-chemical means (e.g., gasification). An analysis that compares the 

various conversion processes and uses of biogas (power, fuel, etc.) could determine the most 

efficient use of biogas sources. Understanding the full resource potential and its geographic 

distribution would help in designing better systems. This analysis does not address the economic 

viability of producing biogas nor the costs for purification. The cost and quality will greatly 

affect the economic feasibility and what applications will compete for its use. These issues will 

be affected by regional policies and incentives that are not accounted for here. A pathway 

assessment of the spatial qualities of the resources to aid either co-digestion or better economies 

of scale in purification technologies was beyond the scope of this initial report. 

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30 

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